Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to bi-functional projectors. In particular, the present disclosure provides a bi-functional projector for implementing a low beam and a high beam efficiently.

BACKGROUND
[0002] Vehicles may be crucial for various individual, as well as commercial purposes. With the advancement in technologies, various improvements may be done in the operational aspects of the vehicles. For example, it may be required for the vehicles, such as Internal Combustion Engine (ICE) vehicles to utilize available power efficiently. As a result, to comply with power conservation requirements, various modifications or alterations may be done in various components of the vehicles.
[0003] This problem may be further aggravated in the case of electric vehicles. With the increase in reliance on electrical vehicles and transformation of automotive powertrain from internal combustion engine to electrically powered systems, such electric vehicles may demand even lesser power consumption, so as to efficiently manage the operational efficiency, range, and performance. In such cases as well, to comply with minimal power consumption requirements, the vehicle may need to alter the manner in which some of the components of the vehicle may operate. However, such modifications may be done keeping in mind the regulatory compliance of the vehicles.
[0004] For example, low beam and high beam functions may be considered to be one of the crucial safety functions of any vehicle. Such use of low beam and high beam may aid the driver of the vehicle in conveniently and safely driving the vehicle. Use of low beam and high beam may be further necessitated at night times, and in severe weather conditions where the visibility may be improper.
[0005] Any efficiency improvement in low beam or high beam may directly contribute to range extension and performance enhancement of the vehicles. Further, increment in the optical efficiency may reduce the power requirement of the system, thereby resulting in improvement of the thermal stability, BOM cost reduction and weight reduction. It may be required to meet such abovementioned requirements, however, without compromising the performance parameters of the vehicle.
[0006] Conventionally, various approaches exist in the art to cater to such requirements. Various types of projectors may be used in headlamps of vehicles. The existing projectors may use specific optics for shaping the light in the primary optics and projecting onto the road by using aspherical lens as secondary optics. However, usage of additional optics for beam shaping results in the loss of light at the interface which reduces overall efficiency.
[0007] Therefore, there exists a need in the art for an efficient bi-functional projector.

SUMMARY
[0008] Embodiments of the present disclosure relate to bi-functional projectors. In particular, the present disclosure provides a bi-functional projector for implementing a low beam and a high beam efficiently.
[0009] An embodiment of the present disclosure pertains to a bi-functional projector for implementing a low beam and a high beam. The bi-functional projector may include a plurality of light sources to define a low beam and a high beam, wherein at least one of the plurality of light sources is to generate a plurality of light beams based on the defined low beam and high beam; a primary optical element to receive at least one of the plurality of light beams from at least one of the plurality of light sources. The primary optical element comprises: a freeform Total Internal Reflective (TIR) surface at an outer face to distribute the plurality of the received light beams; a freeform refractive surface at the centre to cause the plurality of the distributed light beams to travel through the primary optical element; and a planar exit surface. The bi-functional projector may further include a double-sided mirror positioned in a plane parallel to the axis of the primary optical element, wherein the double-sided mirror is to receive and redistribute the plurality of light beams from the primary optical element; and a secondary optical element positioned such that focal point of the secondary optical element is to coincide with the centre point of the edge of the double-sided mirror, wherein the secondary optical element is to collect the light beams and cause the collected light beams to be distributed in a vicinity of the bi-functional projector.
[0010] In another aspect, at least one of the plurality of light sources is a LED light source.
[0011] In yet another aspect, each of the plurality of light sources comprises a controller, and wherein the controller is to implement each of a low beam and a high beam function by directing the plurality of light beams to one of a plurality of specific target zones.
[0012] In yet another aspect, the primary optical element comprises a polymeric medium.
[0013] In yet another aspect, the double-sided mirror is to define a cut-off of low beam.
[0014] In yet another aspect, the secondary optical element is an aspherical lens.
[0015] In yet another aspect, at least some of the plurality of light sources at the top of the primary optical element are configured to define the low beam.
[0016] In yet another aspect, at least some of the plurality of light sources at the bottom of the primary optical element are configured to define the high beam.
[0017] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0019] FIG. 1A depicts a perspective view of an exemplary bi-functional projector, as per an implementation of the present subject matter;
[0020] FIG. 1B depicts a top view of an exemplary bi-functional projector, as per an implementation of the present subject matter;
[0021] FIG. 1C depicts a side view of an exemplary bi-functional projector, as per another implementation of the present subject matter;
[0022] FIG. 2A illustrates a ray diagram of working of an exemplary bi-functional projector, as per an implementation of the present subject matter;
[0023] FIG. 2B illustrates a ray diagram of working of an exemplary bi-functional projector in a low beam function, as per an implementation of the present subject matter;
[0024] FIG. 2C illustrates a ray diagram of working of an exemplary bi-functional projector in a high beam function, as per an implementation of the present subject matter;
[0025] FIG. 3 illustrates an exemplary light distribution pattern of an exemplary bi-functional projector in a low beam function, as per an implementation of the present subject matter; and
[0026] FIG. 4 illustrates an exemplary light distribution pattern of an exemplary bi-functional projector in a high beam function, as per an implementation of the present subject matter.

DETAILED DESCRIPTION
[0027] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosures as defined by the appended claims.
[0028] Embodiments explained herein relate to bi-functional projectors. In particular, the present disclosure provides a bi-functional projector for implementing a low beam and a high beam efficiently.
[0029] As would be appreciated, the approaches of the present subject matter may provide an efficient bi-functional projector, which may then be used in headlamps of automobiles. However, it may be noted that such proposed bi-functional projector may be implemented in any other type of headlamps or auxiliary lamps as well.
[0030] As would be further appreciated, the proposed bi-functional projector may efficiently implement low beam and high beam. Such bi-functional projector may be compact in size, thereby possessing spacing advantage in compact and small vehicles. Even further, the proposed bi-functional projector may use primary optics which may be easy to manufacture using readily available techniques, thereby further increasing the usability.
[0031] The primary optics, as described in the proposed bi-functional projector, may ensure minimum travel of light rays through the medium, polymeric in one example, thereby resulting in less absorption losses and increased optical efficiency. The Total Internal Reflection may also aid in increasing the optical efficiency. Further, the absence of additional optical element at the exit surface may ensure reduction in light loss due to Fresnel loss.
[0032] As would be even further appreciated, the double-sided mirror shield may define the cut off line, and may redistribute the light falling on the surface to the secondary optical element, which in turn may further increase the optical efficiency.
[0033] It may be further noted and appreciated that, since the light sources are positioned in a plane and may be operating a single controller for both high beam and low beam, such aspect may further decrease the number of parts, complexity, and the cost of the manufactured system.
[0034] These and other aspects have been described in further details in conjunction with FIGs. 1-4. It may be noted that these figures are only illustrative, and should not be construed to limit the scope of the subject matter in any manner. It may be further noted that FIGs. 1-2 have been explained together for describing the proposed bi-functional projector, and same reference numerals have been used wherever necessary.
[0035] FIG. 1A, FIG. 1B, and FIG. 1C depict a perspective view, a top view, and a side view respectively, of an exemplary bi-functional projector, as per an implementation of the present subject matter. The bi-functional projector 100 may be used to implement a low beam and a high beam. In one example, the bi-functional projector 100 may be implemented in headlamps of vehicles. However, such example is only illustrative, and not to be construed to limit the scope of the present subject matter in any manner. The bi-functional projector 100 may be implemented in any other types of lamps and auxiliary lamps as well, without deviating from the scope of the present subject matter. Further, the bi-functional projector 100 may be in communication with other optical and electrical components, which have not been depicted in FIGs. 1A-1C for the sake of brevity. Such additional components may be well understood by a person skilled in the art.
[0036] The bi-functional projector 100 may include a plurality of light sources 102-1, 102-2, …, 102-N (collectively and individually referred to as light source 102). In one example, the light sources 102 may be positioned as an array in a planar manner. In another example, the light sources 102 may be implemented as LED lights. However, the same is only illustrative, and other implementations would also be covered within the scope of the present subject matter. The light sources 102 may be implemented as any other light sources, and in any other manner without deviating from the scope of the present subject matter.
[0037] It may be further noted that, although the bi-functional projector 100 may include a plurality of light sources 102, FIG. 1C depicts an exemplary bi-functional projector, such as bi-functional projector 100, with two light sources 102, i.e., 102-1 and 102-2. This has been done only for the sake of clarity. It may be again noted that the same is only illustrative, and not to be construed to limit the scope of the present subject matter in any manner.
[0038] Continuing further, the light sources 102 may be configured to define a low beam and a high beam. In one example, each of the plurality of light sources 102 may include a controller (not depicted in FIGs. 1A-1C). The controller may be implemented as any hardware-based, software-based, or network-based processing resource known to a person skilled in the art.
[0039] Continuing further, the bi-functional projector 100 may further include a primary optical element 104 coupled to the plurality of light sources 102. The primary optical element 104 may include a freeform Total Internal Reflective (TIR) surface 104-2 at an outer face, a freeform refractive surface 104-4 at the centre, and a planar exit surface 104-6. This has been depicted in FIG. 1C. In one example, the primary optical element 104 may include a polymeric medium. However, other implementations are only possible without deviating from the scope of the present subject matter.
[0040] The bi-functional projector 100 may further include a double-sided mirror 106 positioned in a plane parallel to the axis of the primary optical element 104. In one example, the double-side mirror 106 may be implemented as a planar slit in a direction parallel to the axis of the light sources 102 and the axis of the primary optical element 104.
[0041] Continuing further, the bi-functional projector 100 may further include a secondary optical element 108 positioned in such a manner that the focal point of the secondary optical element 108 is to coincide with the centre point of the edge of the double-sided mirror 106. In one example, the secondary optical element 108 may be implemented as an aspherical lens. However, other implementations may also be possible without deviating from the scope of the present subject matter.
[0042] It may be further noted that the manner in which the proposed bi-functional projector 100 operates, is explained in conjunction with FIGs. 2A-2C.
[0043] FIG. 2A illustrates a ray diagram of working of an exemplary bi-functional projector, such as bi-functional projector 100, as per an implementation of the present subject matter.
[0044] In operation, at least one of the plurality of the light sources 102 may be configured to define a low beam and a high beam. Based on the defined low beam and the high beam, the light sources 102 may generate a plurality of light beams.
[0045] In one example, the low beam and the high beam may be defined by the controller of each of the plurality of light sources 102 by directing the plurality of light beams to one of a plurality of specific target zones. For example, to implement the low beam, the controller may cause at least some of the plurality of light sources 102 at the top of the primary optical element 104 to generate the light beams. In a similar manner, to implement the high beam, the controller may cause at least some of the plurality of light sources 102 at the bottom of the primary optical element 104 to generate the light beams.
[0046] It may be noted that any other examples known to a person skilled in the art may also be used to define the low beam and the high beam. All such examples would lie within the scope of the present subject matter.
[0047] Continuing further, the primary optical element 104 may receive at least one of the plurality of light beams from at least one of the plurality of light sources 102. On receiving the light beams, the freeform TIR surface 104-2 at the outer surface may distribute the plurality of the received light beams. The freeform refractive surface 104-4 at the centre may then cause the distributed light beams to travel through the primary optical element 104. As would be appreciated, the freeform TIR surface allows to define the beam pattern in desired direction and shape. Further, the TIR surface may be calculated considering the deviation of ray path occurred due to the propagation of light from rarer medium to denser medium. Such calculation may be done by considering the light source at virtual point to compensate for the deviation of the light path. In another example, the TIR surface may be defined using mathematical modelling and source target mapping methods.
[0048] Continuing further, the light beams upon travelling, may reach the planar exit surface 104-6. As described previously, and would be appreciated, the planar exit surface 104-6 may have no additional optical element. As a result, the light beams may then be refracted through the exit surface 104-6 of the primary optical element 104.
[0049] Continuing further, the double-sided mirror 106 may then receive the light beams and cause the received light beams to redistribute. As would be appreciated, the double-sided mirror 106 may act as a shield and may define the cut-off line of the low beam by restricting the light beam from the different light sources. As would be further appreciated, the double-sided mirror 106 may also reflect a part of the light beam which may be incident on the surface of the mirror 106, thereby further enhancing the optical efficiency of the bi-functional projector 100.
[0050] Thereafter, the secondary optical element 108 may collect the light beams and cause the collected light beams to be distributed in a vicinity of the bi-functional projector 100. In exemplary cases, where the bi-functional projector 100 may be implemented in headlamps of automobiles, the secondary optical element 108 may cause the collected light beams to be distributed on the road environment in the path of the automobile.
[0051] The manner in which the proposed bi-functional projector 100 operates to implement the low beam and the high beam, has been explained below as examples.
[0052] In one example, to implement and generate low beam, the top array of light sources 102 and the primary optical elements 104 may be used. This has been depicted in FIG. 2B. FIG. 2B illustrates a ray diagram of working of an exemplary bi-functional projector in a low beam function, such as bi-functional projector 100, as per an implementation of the present subject matter.
[0053] As depicted in FIG. 2B, light coupled into the primary optical elements 104 from the light sources 102 may be shaped by the freeform refractive centre surface 104-4 and freeform TIR outer surface 104 2. It may be noted that, major part of light beam exiting from the primary optical element 104 may be passed without interacting with the double side mirror shield 106, which may then be refracted through the secondary optical element 108 (depicted as ray bundles BA and BB). The part of light which interacts with the double-sided mirror 106 (depicted as ray bundles AA and AB) may be mapped in such a way that the angle of incidence is kept maximum on the double-sided mirror 106, also referred to as shield 106, so will be the angle of reflection. Thereafter, the reflected light from the double-sided mirror 106 will be incident on the secondary optical element 108 in the half above the axial plane.
[0054] As would be noted, such arrangement will ensure the resultant beam after refracting through the secondary optical element 108 to be directed to the region just below the cut-off line defined by the double-sided mirror 106. This part of light will contribute to the point 75L of LHT of the ECE low beam photometry, thus enhancing the range of the low beam with adequate cut-off sharpness.
[0055] In another example, to implement and generate high beam, the bottom array of light sources 102 and the primary optical elements 104 may be used. This has been depicted in FIG. 2C. FIG. 2C illustrates a ray diagram of working of an exemplary bi-functional projector in a high beam function, such as bi-functional projector 100, as per an implementation of the present subject matter.
[0056] As depicted in FIG. 2C, light coupled into the primary optical elements 104 may be shaped by the freeform TIR outer surface 104-2 and freeform refractive centre surface 104-4. The source target mapping may be done in such a way that the light exiting the primary optical elements 104 is passed through the focus of the secondary optical element 108 which collected by the secondary optical element 108 to generate collimated light with minimum spread and maximum hotspot for high beam.
[0057] As would be noted and appreciated, various exemplary tests were conducted to determine the efficiency and advancement of the proposed bi-functional projector, such as bi-functional projector 100. Result of such exemplary tests have been illustrated in FIGs. 3-4. FIG. 3 illustrates an exemplary light distribution pattern of an exemplary bi-functional projector, such as bi-functional projector 100, in a low beam function as per an implementation of the present subject matter. Further, FIG. 4 illustrates an exemplary light distribution pattern of an exemplary bi-functional projector, such as bi-functional projector 100, in a high beam function as per an implementation of the present subject matter.
[0058] It may be noted that such light distribution patterns, as depicted in FIGs. 3-4 are only exemplary, and not to be construed to limit the scope of the present subject matter in any manner. Any other test results and any other corresponding light distribution patterns would also be possible. All such examples would lie within the scope of the present subject matter.
[0059] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art. 
, Claims:1. A bi-functional projector (100) for implementing a low beam and a high beam, the bi-functional projector (100) comprising:
a plurality of light sources (102) to define a low beam and a high beam, wherein at least one of the plurality of light sources (102) is to generate a plurality of light beams based on the defined low beam and high beam;
a primary optical element (104) to receive at least one of the plurality of light beams from at least one of the plurality of light sources (102), wherein the primary optical element (104) comprises:
a freeform Total Internal Reflective (TIR) surface (104-2) at an outer face to distribute the plurality of the received light beams;
a freeform refractive surface (104-4) at the centre to cause the plurality of the distributed light beams to travel through the primary optical element (104); and
a planar exit surface (104-6);
a double-sided mirror (106) positioned in a plane parallel to the axis of the primary optical element (104), wherein the double-sided mirror (106) is to receive and redistribute the plurality of light beams from the primary optical element (104); and
a secondary optical element (108) positioned such that focal point of the secondary optical element (108) is to coincide with the centre point of the edge of the double-sided mirror (106), wherein the secondary optical element (108) is to collect the light beams and cause the collected light beams to be distributed in a vicinity of the bi-functional projector (100).

2. The bi-functional projector (100) as claimed in claim 1, wherein at least one of the plurality of light sources (102) is a LED light source.

3. The bi-functional projector (100) as claimed in claim 1, wherein each of the plurality of light sources (102) comprises a controller, and wherein the controller is to implement each of a low beam and a high beam function by directing the plurality of light beams to one of a plurality of specific target zones.

4. The bi-functional projector (100) as claimed in claim 1, wherein the primary optical element (104) comprises a polymeric medium.

5. The bi-functional projector (100) as claimed in claim 1, wherein the double-sided mirror (106) is to define a cut-off of low beam.

6. The bi-functional projector (100) as claimed in claim 1, wherein the secondary optical element (108) is an aspherical lens.

7. The bi-functional projector (100) as claimed in claim 1, wherein at least some of the plurality of light sources (102) at the top of the primary optical element (104) are configured to define the low beam.

8. The bi-functional projector (100) as claimed in claim 1, wherein at least some of the plurality of light sources (102) at the bottom of the primary optical element (104) are configured to define the high beam.